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XNRG Humanity Direct Chiltern Challenge

10-Jul-2021 Princes Risborough, Buckinghamshire, UK (England)


Image Mask
Trail Race Race Terrain
50KM / 31Miles
1 Day - 350 Runners

DIFFICULTY Race Difficulty Beginner  

Entry From £0 GBP

Humanity Direct Chiltern Challenge: a 50km, one-day ultra marathon in the picture-perfect Chilterns in aid of funding life-changing operations for children in developing countries.

The ideal 50km introduction to ultra marathon running. Escape to the Chilterns, an area of outstanding natural beauty. What's more, it's FREE to run, if you commit to raising funds for Humanity Direct.

Humanity Direct
In 2019 Humanity Direct raised £24,000 through the three Humanity Direct Ultras, which helped fund life saving and life changing operations for 35 children and we are hoping to raise even more in 2021.

So, how does it work?
It's simple. The entry fee for the one day ultra marathon, is donated to fund a vital operation or, if you prefer, you can enter for free* and start a fundraising page instead and raise as much as you can

*a minimum donation of £58

“The support we’ve had from XNRG has been phenomenal. Thanks to you we’ve rolled out a vital eye-testing programme for children in rural Uganda with over 600 children receiving free glasses so far. Your donations and dedication have also helped us continue to provide lifesaving and life changing surgery for children whose families are live on less then a $1 a day and who would never be able to afford the medical care they need. XNRG ultras truly do change lives!”

- Nick Swift, Humanity Direct’s Founder

This popular race is especially good for those looking for a supportive event for their first ultra within easy reach of London.

As with all of our events, everything is taken care of at the Chiltern Challenge so you can focus on the experience! We’ll provide transfers from the station, free parking, free photos, changing facilities and heaps of tea and cake.

Detailed information about all elements of the Humanity Direct Chiltern Challenge can be found in our event instructions.

The XNRG Chiltern Challenge is a unique chance to get a place on an amazing one day ultra for FREE if you fundraise for a Humanity Direct patient, or donate £58.

Entries will close one week before the event (or when full). A waitlist option will be available if the event becomes fully booked.

Please note: a 2.5% service charge, levied by the registration software, will be added to your total. We are using a new entry system that takes payment through the secure system Stripe. No payment information is retained by Extreme Energy, or our entry system tool.

Our refunds policy: no refunds or deferrals will be made within one month of the event start.

Start / Finish
Start and finish: Princes Risborough School, HP27 0DR

07:00 Minibus pick up starts from Princes Risborough Station
07:00 Registration open
07:30 Walkers briefing
08:00 Walkers Start
08:30 Runners race briefing
09:00 Runners Start
09:30 Elite runners briefing (target time below 6 hours)
10:00 Elite runners start
14:00 Refreshments available
16:00 Prize giving or when enough winners have finished

Minibus to the station running all afternoon

Stretching from the River Thames in Oxfordshire to Hitchin in Hertfordshire, the Chiltern Hills are a spectacular Area of Natural Beauty boasting some of the finest protected countryside in the UK. The well-marked circular route will start and finish at Princes Risborough School, incorporating four checkpoints, approximately 10km apart. Using National Trails and Footpaths, there are clear signposts and post discs, as well as our signs and confidence tape. We'll also give you a handy map, designed to help on any tricky sections. We recommend familiarising yourself with the route before the start of the race - for more information download our full race instructions from our website.

Aid stations and Medical
At each checkpoint, you'll be able to refuel with food and water, as well as accessing any medical assistance if you need it. The event is supported by a Course Manager and a fully qualified medical crew will be in attendance. We strongly recommend taking a moment to read our medical page before booking.

Due to the risk of cross contamination, we cannot provide checkpoint food to suit all dietary requirements. If you require special food or snacks to suit any allergies or vegetarian/vegan diets, can you please bring your own. Put them in containers, marked with your name and checkpoint number and give them to the checkpoint teams at the start of the race.

The only compulsory kit is a fully charged mobile phone and a minimum 500ml of water, but it's worth taking a look at our recommended kit list.
Other equipment may be made compulsory by the race director depending on the weather.

The winners, runners up and age group winners will receive fantastic prizes or vouchers from our sponsors.

Getting to and from the event
A stone's throw from London, there are a few options for reaching the race:

By train
Trains with Chiltern Railways run from London Marylebone every half an hour, taking between 30 and 58 minutes to reach Princes Risborough. Trains from Birmingham leave approximately every 30 minutes and take around 1hr30. We'll be running a minibus shuttle to and from the station in line with registration and finish times.

By road
Princes Risborough is about a 20 minute drive on the A4010 from Junction 4 of the M40 (High Wycombe) or 20 minutes on the B4009 from Junction 6 of the M40. There will be free parking all day at the school.


Event Organiser
Brian Thubron



Elevation: Very little change < 500 metres. Benign running terrain, not technical.

Suitable for: First ultra runners completing a marathon or doing regular long distance running in the last six months.


Elevation: Increase of up to 1000 metres

Suitable for: Runners who have completed at least one ultra distance race (or similar event) or are doing long distance running (>26 miles) regularly, with elevation shown.


Elevation: Increase of up to 1500 metres

Suitable for: Runners who have completed several ultra distances or similar events, or are doing long distance running regularly, with elevation shown.


Elevation: Increase of up to 2000 metres with some challenging climatic conditions (e.g. ice, snow, humidity or heat) and or technical terrain

Suitable for: Experienced runners who have completed at least regular ultra distances in last 12 months, or are doing regular long distance running (>50 miles) with elevation and conditions shown (where possible). Admission to these races may be subject to evidence of recent qualifying race participation and recent medical examination certificate. Check with the race organiser regarding entry requirements.


Elevation: Increase of up to 2000 metres with very challenging climatic conditions (e.g. ice, snow, humidity, heat or at high altitude) and or technical terrain.

Suitable for: Very experienced long distance ultra runners (min 3 years’ experience) or are doing regular long distance running (>50 miles) with elevation and conditions shown (where possible). Admission to these races is often subject to evidence of recent qualifying race participation and recent medical examination certificate. Purchase of specialist kit is often recommended for these races.

Endurance - Multi-activity

Type: An ultra distance race including at least two of the following activities such as running, swimming, cycling, kayaking, skiing and climbing. It may also include different climatic conditions (eg ice, snow, humidity, cold water, mud or heat).

Suitable for: Experienced multi-skilled athletes who have trained for the different activities included in this event. Admission to these races may be subject to receipt of a recent medical examination certificate. Check with the race organiser regarding entry requirements and any specialist equipment required such as a wetsuit, skis or a mountain bike.

Global - Virtual

Type: A virtual race which can be run at any time shown on the dates shown, on any type of terrain in any country.

Suitable for: For runners from beginners to experienced as you choose your own course and challenge based on the guidelines and options set by the virtual race organiser.

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How to tackle your first ultra


Review XNRG Humanity Direct Chiltern Challenge

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12:07 17-07-21

Really enjoyed this race - my first ultra. The route choice is excellent - lots of lovely broadleaf woodland, well marked, great scenery and a little mud for added interest :)

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06:01 16-07-21

2021. Great ultra with good organisation and a nice friendly inclusive atmosphere

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07:54 20-09-18

Did this as my first ultra and was thoroughly spoilt with the organisation of the event and the aid stations that were packed with a good varied selection of food and nibbles. The map was not needed as it was well marked.
Hilly bits throughout but the views through the course were great. Would recommend it for any first timers.
A big thank you to the volunteers at the aid stations who were incredibly helpful in keeping you cool this year in the blazing heat.

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04:18 12-08-18

I did this in 2017 as my first ultra. Can't think of a single negative thing to say. Organisation was top-notch. Markings were flawless. Aid stations were superb.

Highly recommend as a first ultra. Whilst the route is hilly, there's only a few steep bits including the start/end. Poles are not needed and you can use road shoes rather than trail ones if it isn't a wet day (I wore Hoka Cliftons).

Whilst you should bring map/compass/offline-map-on-phone, I didn't need any of them on the day.

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12:56 15-07-18

I have done a number of ultras including repeated events by the organiser of this event. I would put this event down as one of my favourite due to the scenic beauty. I admit it was a sunny day but it was beautiful. A very well sign posted route so didn't need the map that was issued. Good food and water stops and good distances and to finish, a nice medal with a very well designed t shirt that is one of the better t shirts. The size is perfect, its a technical t shirt and has a great picture on the back with simply smart effects on the front. Not nasty attention grabbing advertisement I have become use to. Well done for a top race and Bling.

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10:43 22-07-17

Ran this as my first ultra and was overwhelmed by the support, enthusiasm and energy of everybody involved. The race could not have been better organised or supported, sign-posting was clear, and a lovely quality medal too. Great route and views - would definitely recommend!!

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10:50 21-07-17

This was my first ultra event and I'm already looking forward to running it again next year! The race was organized well, the route was clear, and every 10k or so, there was more than enough refreshments to keep the runners going. Thank you all so much who got involved in the race and cheered us on, that really helped me drive home to finish :)

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10:54 16-06-17

I ran this race as my first ultra after hearing fantastic things about it and it being a 'beginner' intro race to ultra's. What can i say the race is fantastically organised with a cp every 10k or so which are all stock well with water and food, directions on course are great and where you need to cross a road, a volunteer was there to see you across, some stunning scenery on the Chiltern pathway help you tick the miles off and its a friendly race. fully recommend this race so much i'm running it again this year.

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09:11 05-08-16

A fantastic race for all abilities. A short drive from London in a beautiful location. The route was varied with forest trails and open fields. Terrain in undulating with plenty of runnable sections. CPs are perfectly spaced and sticked up with all the right food and plenty to choose from, from homemade rocky roads to peanut butter and nutella sandwiches. Staff are very friendly and relaxed. The whole race has a brilliant atmosphere and it was a pleasure to take part this year! Nothing negative to say! Thank you XNRG! Marina

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02:29 27-07-16

My first ultra event and what else can I say but "outstanding". From the friendly welcome at the registration desk and the relaxed atmosphere to the perfectly marked course and supreme organisation. I have been running competitively on the road up to half marathon for about 4 years but had never completed anything like this. In fact I have only completed one marathon and that was a last minute entry given to me. This was potentially a daunting event but Extreme Energy have come up with a perfect event here. It had the perfect balance of a friendly and relaxed atmosphere, ideal for first timers and a challenging course with a reasonably good level of runner at the front of the pack. Can not wait to try another of Extreme Energy's events. Thank you.

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